Recent developments in ultra low sulfur (ULS) fuel have improved fuel efficiency and created cleaner exhaust gases. Globally, the permitted sulfur limit in fuel oils has been decreased to 10ppm in many countries and regions. For compliance verification, X-ray fluorescence (XRF) spectrometry is the definitive analysis tool for use at distribution terminal and refineries, as well as mobile or stationary testing laboratories. In recent years, there has been an increasing need for an instrument which does not require the use of helium gas, for instances, when acquisition or delivery of helium to the analysis site is difficult. The Micro-Z ULS (ultra low sulfur) is a newly developed Sulfur analyzer which does not require helium gas in operation. This application note demonstrates that Micro-Z ULS can meet the requirements of